Date:   Wed, 6 May 2020 22:10:23 +0300
From:   Grygorii Strashko <grygorii.strashko@...com>
To:     Rob Herring <robh@...nel.org>
CC:     Richard Cochran <richardcochran@...il.com>,
        Murali Karicheri <m-karicheri2@...com>,
        "David S. Miller" <davem@...emloft.net>,
        Tero Kristo <t-kristo@...com>,
        Lokesh Vutla <lokeshvutla@...com>,
        netdev <netdev@...r.kernel.org>, Sekhar Nori <nsekhar@...com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>, Nishanth Menon <nm@...com>
Subject: Re: [PATCH net-next 1/7] dt-binding: ti: am65x: document common
 platform time sync cpts module



On 06/05/2020 22:07, Rob Herring wrote:
> On Tue, May 5, 2020 at 10:01 AM Grygorii Strashko
> <grygorii.strashko@...com> wrote:
>>
>>
>>
>> On 05/05/2020 07:04, Rob Herring wrote:
>>> On Fri, May 01, 2020 at 11:50:05PM +0300, Grygorii Strashko wrote:
>>>> Document device tree bindings for TI AM654/J721E SoC The Common Platform
>>>> Time Sync (CPTS) module. The CPTS module is used to facilitate host control
>>>> of time sync operations. Main features of CPTS module are:
>>>>     - selection of multiple external clock sources
>>>>     - 64-bit timestamp mode in ns with ppm and nudge adjustment.
>>>>     - control of time sync events via interrupt or polling
>>>>     - hardware timestamp of ext. events (HWx_TS_PUSH)
>>>>     - periodic generator function outputs (TS_GENFx)
>>>>     - PPS in combination with timesync router
>>>>     - Depending on integration it enables compliance with the IEEE 1588-2008
>>>> standard for a precision clock synchronization protocol, Ethernet Enhanced
>>>> Scheduled Traffic Operations (CPTS_ESTFn) and PCIe Subsystem Precision Time
>>>> Measurement (PTM).
>>>>
>>>> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
>>>> ---
>>>>    .../bindings/net/ti,k3-am654-cpsw-nuss.yaml   |   7 +
>>>>    .../bindings/net/ti,k3-am654-cpts.yaml        | 152 ++++++++++++++++++
>>>>    2 files changed, 159 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml b/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml
>>>> index 78bf511e2892..0f3fde45e200 100644
>>>> --- a/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml
>>>> +++ b/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml
>>>> @@ -144,6 +144,13 @@ patternProperties:
>>>>        description:
>>>>          CPSW MDIO bus.
>>>>
>>>> +  "^cpts$":
>>
>> ok
>>
>>>
>>> Fixed strings go under 'properties'.
>>>
>>>> +    type: object
>>>> +    allOf:
>>>> +      - $ref: "ti,am654-cpts.yaml#"
>>>> +    description:
>>>> +      CPSW Common Platform Time Sync (CPTS) module.
>>>> +
>>>>    required:
>>>>      - compatible
>>>>      - reg
>>>> diff --git a/Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml b/Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml
>>>> new file mode 100644
>>>> index 000000000000..1b535d41e5c6
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml
>>>> @@ -0,0 +1,152 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/net/ti,am654-cpts.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: The TI AM654x/J721E Common Platform Time Sync (CPTS) module Device Tree Bindings
>>>> +
>>>> +maintainers:
>>>> +  - Grygorii Strashko <grygorii.strashko@...com>
>>>> +  - Sekhar Nori <nsekhar@...com>
>>>> +
>>>> +description: |+
>>>> +  The TI AM654x/J721E CPTS module is used to facilitate host control of time
>>>> +  sync operations.
>>>> +  Main features of CPTS module are
>>>> +  - selection of multiple external clock sources
>>>> +  - Software control of time sync events via interrupt or polling
>>>> +  - 64-bit timestamp mode in ns with PPM and nudge adjustment.
>>>> +  - hardware timestamp push inputs (HWx_TS_PUSH)
>>>> +  - timestamp counter compare output (TS_COMP)
>>>> +  - timestamp counter bit output (TS_SYNC)
>>>> +  - periodic Generator function outputs (TS_GENFx)
>>>> +  - Ethernet Enhanced Scheduled Traffic Operations (CPTS_ESTFn) (TSN)
>>>> +  - external hardware timestamp push inputs (HWx_TS_PUSH) timestamping
>>>> +
>>>> +   Depending on integration it enables compliance with the IEEE 1588-2008
>>>> +   standard for a precision clock synchronization protocol, Ethernet Enhanced
>>>> +   Scheduled Traffic Operations (CPTS_ESTFn) and PCIe Subsystem Precision Time
>>>> +   Measurement (PTM).
>>>> +
>>>> +  TI AM654x/J721E SoCs has several similar CPTS modules integrated into the
>>>> +  different parts of the system which could be synchronized with each other
>>>> +  - Main CPTS
>>>> +  - MCU CPSW CPTS with IEEE 1588-2008 support
>>>> +  - PCIe subsystem CPTS for PTM support
>>>> +
>>>> +  Depending on CPTS module integration and when CPTS is integral part of
>>>> +  another module (MCU CPSW for example) "compatible" and "reg" can
>>>> +  be omitted - parent module is fully responsible for CPTS enabling and
>>>> +  configuration.
>>>
>>> That's fine, but you should still have compatible and reg.
>>
>> I'll add reg as below. But compatible is an issue, because
>> k3-am654-cpsw-nuss call of_platform_populate() to create mdio device.
>> But for CPTS I do not want to create device as k3-am654-cpsw-nuss uses direct
>> function calls to CPTS.
>>
>> Will it be correct to switch to of_platform_device_create() instead of
>> of_platform_populate()?
> 
> That should be fine I think.

Thanks. I've sent follow up patches.

-- 
Best regards,
grygorii

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